A related art dishwasher will be described with reference to the attached drawings.
Referring to FIG. 1, the related art dishwasher is provided with a tub 1 having upper/lower arms 4/5, upper/lower racks 6, and 7, and a driving unit 10 mounted therein.
The driving unit 10 has upper/lower connection pipes 2, and 3 connected thereto for pumping washing water, and a drain hose 9 connected thereto for draining the washing water, and the upper/lower connection pipes 2, and 3 have upper/lower spray arms 4, and 5 connected thereto. Over the upper spray arm 4, there is an upper rack 6, and over the lower spray arm 5, there is a lower rack 7.
The upper/lower spray arms 4, and 6 are rotatably mounted over the driving unit 10. The spray arms have spray holes formed therein for spraying washing water to the racks, respectively. Moreover, the lower spray arm has an additional spray hole for spraying away soil from a filter on the driving unit.
The driving unit of the dishwasher will be described in detail with reference to FIG. 2.
The driving unit of the dishwasher is provided with a sump 20 for holding the washing water therein, a heater 30 at the sump for heating the washing water, a washing pump 40 at the sump for pumping the washing water, a drain pump 50 at the sump for draining the washing water, and filtering means for guiding a portion of the washing water pumped thus, and filtering rest of the washing water.
The sump 20 has a washing water holding portion 21 for holding the washing water therein actually, and a drain chamber 22 separate from the holding portion 21. On an outside of the washing water holding portion, there is a flow control unit 25 having a flow control valve 26 coupled thereto with a shaft.
The washing pump 40 is provided with a washing motor 41 under the sump 20 for generating driving force, and an impeller 42 at the filtering means for pumping the washing water. The impeller is coupled to the washing motor with a shaft.
The drain pump 50 is mounted to the drain chamber 22. The drain pump is provided with a drain motor, and an impeller.
The filtering means is provided with a pump housing 60 having a space for mounting the impeller 42 thereto, a filter housing 70 for covering the pump housing, and a cover 80 for covering the filter housing and the sump. Under the filter housing, there is the pump housing, and over the filter housing there is the cover.
The filter housing has a soil chamber 75, and so on, and the soil chamber has a drain 75a in communication with the drain chamber 22. The drain 75a is projected downward from the soil chamber 75 at a predetermined length and inserted in the drain chamber 22. The filter housing will be described in detail, later.
The cover 80 has a filter 81 mounted thereon opposite to the soil chamber 75 in the filter housing 60, and on an outer side of the filter 81, there are a plurality of recovery holes 82. The recovery holes 82 are in communication with the sump 20.
The filter housing will be described with reference to FIG. 3.
The filter housing 70 is provided with a washing water inlet 72 for introduction of the washing water pumped by the impeller 42 thereto, main flow passages 73a, and 73b and a sampling flow passage 74 connected to the washing water inlet, and the soil chamber 75 connected to the sampling flow passage. To the drain 75a of the soil chamber, there is a valve mounted thereon for draining the washing water and the soil from the soil chamber to the drain chamber in draining.
Rotatably mounted on the washing water inlet 72 of the filter housing 70, there is a flow control valve 26 for opening/closing the main flow passages, and the flow control valve is coupled to the flow change-over unit 25 at the sump 20 with a shaft. On a circumference of the flow control valve 26, there is a rib 26a for opening/closing the main flow passages.
The operation of the dishwasher will be described.
The dishwasher washes dishes while the dishwasher performs cycles of pre-washing, main washing, rinsing, heated rinsing, and drying, in a sequence, or selectively. Between the cycles, a drain cycle is performed. The main washing cycle will be described.
Upon starting the main washing, the impeller 42 rotates following rotation of the washing motor. As shown in FIG. 4, the impeller pumps washing water (including detergent) from the sump 20 to the washing water inlet 72 in the pump housing 60.
Referring to FIGS. 5 and 6, the flow control valve 26 opens the two main flow passages 73a, and 73b selectively or at the same time following rotation of the flow control unit 25. According to this, a portion of washing water at the washing water inlet 72 is introduced to the upper and/or lower spray arms 4, and 6 through the main flow passages 73a, and 73b, and rest of the washing water is introduced to the soil chamber 75 through the sampling flow passage 74.
In this instance, the flow control valve 26 opens the two main flow passages 73a, and 73b at the same time, or alternately, for supplying the washing water to both of the upper/lower spray arms.
At the same time with this, there is a portion of the washing water always introduced to the sampling flow passage 74 regardless of the flow control valve 26 opening of any one of the main flow passages.
The washing water is introduced from the sampling flow passage to the soil chamber 75 directly, and overflows therefrom through the filter 81 on the soil chamber, when the filter 81 filters foreign matters from the washing water.
The washing water filtered thus, and the washing water fallen down from the upper/lower spray arms is introduced to the sump 20 through the recovery holes 82 in the cover 80, again.
Though it appears that only a portion of the washing water is filtered for a short time period, almost all of the washing water is filtered during the main washing cycle.
Upon completion of the washing cycle, a drain cycle is started.
Upon starting of the drain cycle, the drain pump 50 is put into operation. In this instance, the washing water and the soil are drawn from the sump 20 by the drain pump 50. At the same time with this, as shown in FIG. 5B, the washing water and the soil are drawn from the soil chamber 75 through the drain 75a by the drain pump 50. The washing water and the soil introduced to the drain pump 50 thus are drained to an outside of the dishwasher through the drain hose 9.